Defibrillation testing should be routinely performed at the time of implantable cardioverter-defibrillator implantation Contra Fernando Arribas Cardiology Service Hospital 12 de Octubre Madrid Spain
D.O.I. Declaration of Interest Honoraria from: Boston Scientific Medtronic St. Jude Medical Böhringer Ingelheim Merck Sanofi Aventis Bayer Institutional funding from: Boston Scientific Medtronic St Jude
G. Klein s Debaters Rules Rephrase the question to suit your argument Degrade your opponent whenever possible Use anecdotal data abundantly Obfuscate data not fitting your hypothesis Appeal to non available randomized trials Quote Framingham at least once Be patronizing to the chairmen Appeal to the worst instincts of the audience Quote your opponent out of context from previous publications George Klein email communication, September 2003
Defibrillation testing should be routinely performed at the time of implantable cardioverter-defibrillator implantation adverb as a normal part of a job or process repeatedly, and unsurprisingly adjective performed as part of a regular procedure rather than for a special reason
Evidence Based Medicine A Randomized-Clinical Trial to Assess the Safety and Predictive Value of Intra-Operative Defibrillation Testing of Implantable Defibrillators All ICD and/or CRT initial implants R 1:1 DFT testing @ implant no testing @ implant Assess safety Assess efficacy
(Am Heart J 2010;159:98-102.) (J Cardiovasc Electrophysiol, Vol. 19, pp. 400-405, April 2008) (J Cardiovasc Electrophysiol, Vol. 17, pp. 140-145, February 2006)
What are we testing Induced VF: someway different from spontaneous VF Shock on T or 50 Hz nothing to do with ischaemia, myocardial stress, Autonomic NS Different VF means different probability for defibrilation (DFT) Spontaneous VF is faster and less organized than induced Organization correlates with probability for termination Differences in the activation patterns between sustained and self-terminating episodes of human ventricular fibrillation. Mäkikallio TH, Huikuri HV, Myerburg RJ, Seppänen T, Kloosterman M, Interian A Jr, Castellanos A, Mitrani RD. Ann Med. 2002;34:130-5.
How are we testing DF Threshold for stimulation: yes or no Defibrillation Threshold: probabilistic value 80% 20% Strickberger SA et al. Circulation 1997;96:1217 1223. Marchlinski FE et al. Am J Cardiol 1988;62:393 398. Neuzner J et al. Am J Cardiol 1999;83:34D 39D. From DFT to Safety margin: Successful defibrillation with two shocks consecutive? more than 10 J under the maximum energy of the device. Or even one!
Why are we testing DF? Most of implanted ICDs will never treat a VF episode Appropriate shocks Average per year 5,1% Appropriate shocks 8% 1 year 23% 5 Year Only 30% of patients will receive an appropriated therapy (2-4 y) Should a ventricular arrhythmia occur, the most probable is VT VT has a different mechanism and then a different role for ATP
Why are we testing DF? Bayesian analysis The high pre-test probability of success reduces the value of testing What if negative? Is it a false negative result? Good DFT in 95% of cases Average DFT for single coil 8-10 J and 10-12 J for double coil Safety margin > 10J in 97,8 % of cases
Why are we testing DF? The test could be not predictive A percentage of failing energies may defibrilate at a second attempt 7-17% of energies 10-15 J over DFT may fail Ischemic VF requires higher energy to terminate than induced VF without ischaemia in animal models
Why are we testing DF? The test is not predictive The first defibrillation shock of 20 J was delivered. If unsuccessful, a transthoracic rescue shock was applied. If the first defibrillation attempt at 20 J was successful, the second defibrillation attempt was to be performed with a 10-J shock. If the first attempt of 20 J was unsuccessful, the second attempt was to be performed with a 30-J shock. No further VF inductions were recommended regardless of defibrillation success after the second induction.
Why are we testing DF? The test is not predictive PACE 2009; 32:573 578
Why are we testing DF? DFT is not absolutely safe: risk from VF and from shocks There were a total of 19,067 ICD implants during the study period. There were: 3 DFT testing related deaths 5 DFT testing related strokes 27 episodes that required prolonged resuscitation (2 patients had significant clinical sequelae) DFT was performed in 80% of cases
ICD implant complications Brignole Credit Simpson Russo Birnie Swerdlow Ave. Death 0.07 0 0.35 0.01 0.05 CVA/TIA 0.05 0.6 0.03 0.05 PE/NCNS-SE 0.02 0.6 0.1 MI 0.7 0 1.0 0.9 CPR/IABP 0.15 + 0.11 0 0.18 0.5 0.2 Heart Failure 3.6 0.4 1.5 Aspiration, intubation 0 0.1 0.1 Arterial Line Complication 0 0.4 0.2 ICU stay 9 0.5 /3.6
What about real life 1997 2003 4,7 % no DFT 1996 2003 24 % no DFT 2007 2010 67 % no DFT 2006 2007 36 % no DFT 2008-2009 61% no DFT
Methods The SAFE-ICD study was a multicenter, prospective, longitudinal, observational study designed to assess the safety of DT performed during the implantation procedure, and DT strategies in consecutive patients undergoing de novo ICD insertion. No deviation from the centers current practice was introduced by this study protocol. Results Overall, 836 (39%) patients had DT performed during the ICD insertion procedure and 1,284 (61%) did not. Safety margin data were available for 695 patients in the DT group: a safety margin > 10 J was present in 648 (93%) patients and< 10 J in 47 (7%).
Although fairly balanced, DT patients had less severe underlying structural heart disease than non DT patients, as evidenced by lower rate of congestive heart failure, New York Heart Association functional class III or IV, atrial fibrillation, higher ejection fraction, and less usage of diuretics and digoxin
Defibrillation testing should NOT be routinely performed at the time of implantable cardioverter-defibrillator implantation